The present invention relates to the process control industry. More specifically, the present invention relates to diagnostics of pressure sensors of a type for use in the process control industry to measure pressure of a process fluid.
Pressure transmitters are used in the process control industry to measure pressure of a process at a remote location and transmit pressure information over a two-wire process control loop to a control room where the process is controlled. The transmitter includes a pressure sensor which is used for sensing an absolute or differential pressure of the process. Differential pressure is used, for example, to measure process flow by monitoring the change in pressure across a constriction.
As the pressure sensors are exposed to a harsh working environment, their accuracy tends to degrade over time. Thus, to maintain accurate pressure measurements, it is necessary to periodically replace or calibrate the sensor. Calibration requires an operator to enter the field, remove the pressure sensor and apply a test pressure. This is time consuming, dangerous and may require the process to be shut down during calibration. A pressure transmitter capable of performing diagnostics on a pressure sensor without requiring the transmitter to be taken off line and disconnected from the process would be a useful contribution to the process control industry.